Giving blood transfusions to adult dengue patients with low blood platelet counts and without severe bleeding is ineffective, reported The Star Online recently. This was according to research carried out in Malaysian and Singaporean hospitals that was published in The Lancet on March 8.
The news portal quoted University Malaya Medical Centre (UMMC) infectious diseases unit head Sharifah Faridah Syed-Omar as saying “the study showed that routine platelet transfusions did not lead to early platelet count recovery or prevent clinical (moderate) or severe bleeding from occurring.”
“Based on this study, we do not recommend routine platelet transfusion in patients with dengue fever,” she said. Sharifah, who led the team from UMMC for Malaysia’s contribution in the study, said this in a statement issued by UM on March 9.
The findings were based on clinical trials carried out from April 29, 2010 to Dec 9, 2014, by Tan Tock Seng Hospital and three other hospitals in Singapore, and UMMC that recruited 372 dengue patients. The patients were aged at least 21 years with confirmed or probable dengue and thrombocytopenia (low platelet count) without persistent mild bleeding or any severe bleeding.
“The mainstay of treatment for dengue remains supportive with careful administration of fluids to treat plasma leakage that occurs in severe dengue,” the statement said.
It added that bleeding did not stop in patients with low platelet counts who did not suffer severe bleeding despite being given platelet transfusions compared to patients who were not. The study also found that there were “significantly more adverse events in transfused patients, although all events were resolved.”
It added that “given the scarcity of blood products and the potential safety concerns of blood products in resource-limited settings, the platelet transfusion for uncomplicated dengue patients cannot be recommended since there was no benefit in the reduction of moderate or severe bleeding or any improvement in platelet count recovery.”
Dengue fever vaccine almost at hand
In a clinical trial led by the Johns Hopkins Bloomberg School of Public Health, a single-dose dengue vaccine was 100% effective in preventing human volunteers from contracting the virus.
The findings, published in mid-March in Science Translational Medicine, could be the final puzzle piece in developing an effective vaccine. There are four different strains of dengue, and a successful vaccine must prevent all four.
The TV003 vaccine, developed by scientists at the National Institutes of Health, was already effective in preventing dengue 1, 3, and 4 viruses, but the portion of the vaccine that was designed to prevent dengue 2 did not induce as strong an immune response as the other three components.
So the researchers decided to see if the vaccine could specifically protect against the dengue 2 virus if people were exposed to that strain six months after being vaccinated. For this study, the researchers looked for the evidence of actual infection: virus in the blood, rash, and low white blood cell count.
In the investigation, researchers from the Bloomberg School and the University of Vermont administered the TV003 dengue vaccine to 24 healthy adults, while 24 others received a placebo. Six months later, the remaining 41 study participants were exposed to the dengue 2 virus.
None of the 21 who had received the vaccine had any evidence of infection in their blood, nor did they develop a rash or have low white blood cell counts.
In contrast, 100% of the 20 placebo recipients had virus in their blood, 80% developed a rash, and 20% had low white blood cell counts. The researchers believe the effects will be long-lasting and that only a single dose of the vaccine is necessary.